Synthesis of N-H Carbazoles via Ir-catalyzed Intramolecular C-H Amination

Miura et al. have reported the synthesis of N-H carbazoles via Ir-catalyzed intramolecular C-H amination. According to their results, a dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of catalytic amounts of [Cp*IrCl₂]₂ and Cu(OAc)₂ and 2 equivalents of pivalic acid under aerobic conditions to produce the corresponding N-H carbazoles. This reaction provides a straightforward, step- and atom-economical synthetic route to N-H carbazoles. Furthermore, a relevant dimerization reaction of 2-aminobiphenyl under similar iridium catalysis has also been reported.